Currently, the user's certification and settlement methods of different electric vehicle charging piles vary widely, which greatly reduces the user charging operation convenience and security. Therefore, this paper presents a new type of certification settlement unit which can be used on various charging piles. The design idea is to divide the charging pile into two parts:the charging control unit and the authentication settlement unit. The charging control unit is mainly responsible for charging control and communication with vehicles. The certification settlement unit is mainly responsible for human-computer interaction, user authentication, metering and billing, settlement payment and remote communication. It introduces concisely the overall design scheme, hardware structure and software structure of the certification settlement unit, and describes the realization process of the main business, such as bidirectional authentication, charging start, stop charging settlement and charging completion settlement in detail. It is proved by practice that the design forms the standard charging operation flow and standardizes the users’ certification and settlement method effectively, which greatly improves the convenience and security of user charging operation. This work is supported by National Key Research and Development Program of China (No. 2016YFB0101800).